Fix crash when an invalid callback function is passed to CURLMOPT_PUSHFUNCTION

Previously this caused a SIGABRT.

Closes GH-11639.

Author: nielsdos

NEWS

@@ -13,6 +13,10 @@ PHP                                                                        NEWS
     (ilutov)
   . Fixed use-of-uninitialized-value with ??= on assert. (ilutov)
 
+- Curl:
+  . Fix crash when an invalid callback function is passed to
+    CURLMOPT_PUSHFUNCTION. (nielsdos)
+
 - Date:
   . Fixed bug GH-11368 (Date modify returns invalid datetime). (Derick)
 

ext/curl/multi.c

@@ -382,6 +382,11 @@ static int _php_server_push_callback(CURL *parent_ch, CURL *easy, size_t num_hea
 		return rval;
 	}
 
+	if (UNEXPECTED(zend_fcall_info_init(&t->func_name, 0, &fci, &t->fci_cache, NULL, NULL) == FAILURE)) {
+		php_error_docref(NULL, E_WARNING, "Cannot call the CURLMOPT_PUSHFUNCTION");
+		return CURL_PUSH_OK;
+	}
+
 	parent = Z_CURL_P(pz_parent_ch);
 
 	ch = init_curl_handle_into_zval(&pz_ch);
@@ -395,8 +400,6 @@ static int _php_server_push_callback(CURL *parent_ch, CURL *easy, size_t num_hea
 		add_next_index_string(&headers, header);
 	}
 
-	zend_fcall_info_init(&t->func_name, 0, &fci, &t->fci_cache, NULL, NULL);
-
 	zend_fcall_info_argn(
 		&fci, 3,
 		pz_parent_ch,

ext/curl/tests/curl_pushfunction_nonexistent_callback.phpt

@@ -0,0 +1,54 @@
+--TEST--
+Test CURLMOPT_PUSHFUNCTION with non-existent callback function
+--CREDITS--
+Davey Shafik
+Kévin Dunglas
+Niels Dossche
+--EXTENSIONS--
+curl
+--SKIPIF--
+<?php
+include 'skipif-nocaddy.inc';
+
+$curl_version = curl_version();
+if ($curl_version['version_number'] < 0x080100) {
+    exit("skip: test may crash with curl < 8.1.0");
+}
+?>
+--FILE--
+<?php
+// Test adapted from curl_pushfunction.phpt
+
+$mh = curl_multi_init();
+
+curl_multi_setopt($mh, CURLMOPT_PIPELINING, CURLPIPE_MULTIPLEX);
+curl_multi_setopt($mh, CURLMOPT_PUSHFUNCTION, "nonexistent");
+
+$ch = curl_init();
+curl_setopt($ch, CURLOPT_URL, "https://localhost/serverpush");
+curl_setopt($ch, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_2_0);
+curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
+
+curl_multi_add_handle($mh, $ch);
+
+$active = null;
+while(true) {
+    $status = curl_multi_exec($mh, $active);
+
+    do {
+        $info = curl_multi_info_read($mh);
+        if (false !== $info && $info['msg'] == CURLMSG_DONE) {
+            $handle = $info['handle'];
+            if ($handle !== null) {
+                curl_multi_remove_handle($mh, $handle);
+                curl_close($handle);
+                break 2;
+            }
+        }
+    } while ($info);
+}
+
+curl_multi_close($mh);
+?>
+--EXPECTF--
+Warning: curl_multi_exec(): Cannot call the CURLMOPT_PUSHFUNCTION in %s on line %d